I found this Thai style recipe by Liz Neumark on a website called Food Republic. I changed some ingredients' amounts and added extra garnish. Also, I made it with both scallops and shrimp. I boiled the shrimp in salted water with a sprinkle of dried lemongrass. When the scallops were done, I added the shrimp to the wok so they would pick up some of the marinade flavor.
Whisk together 2 tablespoons olive oil, tarragon, lime zest and juice, half of each the garlic, minced onion and ginger in a sealable container. Add scallops, toss to coat, refrigerate for at least 30 minutes.
Prepare the broth:
Heat the grape seed or vegetable oil in a medium saucepan over medium heat; add the remaining onions and slowly sauté until they are carmelized but not burned. Add the remaining garlic and ginger and stir for about 1 minute.
Add the lemongrass and fish sauce to the pan and stir until fragrant, about 1 minute, then pour in the stock. Bring the sauce to a boil, then reduce the heat and simmer for about 20 minutes. Pour in the coconut milk and simmer for about 5 minutes longer. Set the sauce aside and keep it warm.
Meanwhile, drain the scallops of excess marinade and set them on paper towels for a minute or so to dry. Place a large wok over medium heat for about 2 minutes, then coat the surface with the remaining 2 teaspoons olive oil. When the oil is hot, gently add the scallops to the skillet without crowding them.
Cook the scallops on one side for about 2 minutes, or until they are browned. Do not move them about or the searing process will be affected. Turn the scallops over and cook for 2 more minutes. (I had huge scallops and need at least 4 minutes per side.)
To serve, pour some of the warm sauce onto individual plates and set the scallops on the sauce; garnish with the scallions and place the rice to the side.